Estimation of Genetic and Phenotypic Correlations and Genetic Trends for Wool Traits of Menz Sheep Breed in Central Ethiopia

Abstract

The primary objective of the study was to investigate the genetic correlations and genetic trends of wool traits of Menz sheep breed in the central highland of Ethiopia. Selection for yearling live weight and greasy fleece weight of Menz sheep combined in an economic index has been implemented since1998. In this study yearling live weight (YLW), yearling grease fleece weight (YGFW) and yearling staple length (YSL) traits were included. Data were collected over a period of 9 years (1998–2006) from Menz sheep breed maintained at Debre Birhan Agricultural Research Center, Ethiopia. Genetic and phenotypic correlations were estimated by average information restricted maximum likelihood (AIREML) with fitting in multi-traits (three traits) animal models. Phenotypic and genetic correlations between all traits were positive, except for yearling staple length and yearling live weight. Genetic trends for yearling grease fleece weight were positive and highly significantly (p<0.01) different over time whereas genetic trend for yearling staple length was significantly (p< 0.05) decreased over time. This study concludes that moderate genetic progress for wool traits can be achieved in Menz sheep flock by selection. In addition, the genetic correlations and genetic trend in this study can be used as input parameters to optimize breeding program for integrated improvement of wool.